Introducing the ghost of Paris Hilton
The socialite-turned-reality-TV-star wore a white sheet embellished with two black eyes and a lush red mouth and played the theremin (an instrument consisting of two metal antennas which sense the position of the player's hands and control oscillators for frequency with one hand, and volume with the other. -- Wikipedia)
On Sunday, Hilton tweeted the above pic along with this query: "What do you all think of the ghost costume I wore on stage at The @Deadmau5 show?" To which Mil_Angry_Bird replied "confirmed!!!! pretty ghost!!!"
So there you have it.